Supporting arm for a screen



FIG. 1 is a perspective view of a supporting arm for a screen, showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a top view thereof;

FIG. 7 is a bottom view thereof;

FIG. 8 is another perspective view thereof; and,

FIG. 9 is a perspective view showing an embodiment of the claimed design, wherein the broken lines are shown for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a supporting arm for a screen, as shown and described. 